Me at exactly 89kgs in a 172 cup with a full tank versus a friend weighing 60kgs in a 172 with an empty tank would be remarkably similar in weight, In fact I could only prey they hadnt removed their spare as well or id be a spec in their rear view mirror!!
No I really drive a std 172 but test drove a cup before I bought mine, I went for mine because It was better condition, the only other reason was that I found the suspension a little to hard on the cup.
Having said that I travel 50 miles to work and back on dual carriageway, if I could take a direct route along b roads I probably would have chosen the cup for 1. the suspension and 2. the colour